1. Field of the Invention
The present invention relates to a structure for mounting a spring member supporting a seat occupant on a seat frame for a vehicle.
2. Description of Related Art
The seat frame for a vehicle is provided with a spring member such as an S spring to support the seat occupant, and the spring member is positioned and mounted relative to the seat frame. In the seat frame for a vehicle as described in Japanese Patent Application Publication No. 2002-225600 (JP 2002-225600 A), a portion of a rear pipe or a front pipe connecting a pair of left and right side frames is diameter-expanded by a hydroforming process to provide a large-diameter portion, such that both ends in a width direction of a retainer having an S-shaped cross section provided at a terminal of the S spring abut on and are clipped at the large-diameter portion of the seat frame.
In the technology described in JP 2002-225600 A, both ends in the width direction of the retainer abut on and are clipped between the large-diameter portions provided on a portion of the rear pipe or the front pipe in the width spacing of the retainer. Nevertheless, it is possible that only one end in the width direction of the retainer abuts on the large-diameter portion to clip the S spring at the rear pipe or the front pipe. When the latter clipping method is incorrectly adopted, a misassembly is caused. In this case, the inherent function of the S spring cannot be fulfilled, so there is a possibility that the seat occupant cannot be firmly supported. Further, the formation of the large-diameter portion by subjecting a portion of the rear pipe or the front pipe to a hydroforming process would add processing steps and cause an increase in cost.